Conventionally, a diaphragm-type pressure sensor such as described in PTL1 is known as a compact pressure sensor. The diaphragm-type pressure sensor detects a difference in pressures applied to both front and back sides of the diaphragm as deformation of the diaphragm. However, this type of pressure sensor has a problem of damaging the diaphragm when an excessive pressure is applied thereto.
As a pressure sensor that solves such a disadvantage of the diaphragm-type pressure sensor, a pressure sensor utilizing viscous drag of gas has been proposed see PTL2). The pressure sensor causes a movable comb to oscillate in relation to a fixed comb and detects pressure by utilizing viscous drag of gas between the combs.